A standard such apparatus has a reaction vessel, at least one reaction gas supply and at least one reaction liquid supply. It is possible, for example, to employ such an to produce methane hydrate or methane clathrate. To this end, methane gas and water are introduced into a reactor or into a reactor vessel at pressures of typically more than 60 bar and temperatures around 0° C. Under the above-referenced reaction conditions, a gas-inclusion compound is formed in which methane gas is contained in cavities of ice crystals. This prior-art apparatus is used in a discontinuous operation, with the result that the production of methane hydrate is done in batches. As a result, the production of larger quantities of gaseous clathrate is very expensive, inefficient from an energy point of view, and thus uneconomical when using the prior-art apparatuses.